Release fluid applicator

ABSTRACT

An applicator-cleaner for applying a release and off-set preventing fluid to the surface of a cylindrical pressure fixing roller and for cleaning developer powder therefrom in which a rigid frame formed with one surface having two longitudinal edge areas separated by a central recess extending the length thereof has a wicking blanket, containing a release and off-set preventing fluid, stretched across its one surface to contact the two longitudinal edge areas. The frame is resiliently biased to forcibly engage the portions of the wicking blanket over the longitudinal edge areas of the frame against the pressure fixing roller.

U Unlted States Patent 1111 3,859,957

Larson Jan. 14, 1975 RELEASE FLUID APPLICATOR Primary Examiner-Mervin Stein R ll M [75] Inventor ogerL Larson Rose e mn Assistant Examiner-Douglas A. Salser Assigneel Minnesota M g & Manufacturing Attorney, Agent, or FirmAlexander, Sell, Steldt &

Company, St. Paul, Minn. DeLaHunt [22] F1led: Oct. 23, 1973 ABSTRACT [21] Appl' N04 408,538 An applicator-cleaner for applying a release and offset preventing fluid t0 the surface of a cylindrical pres- 52 U.S. c1 118/70, 118/264, 118/269, Sure fixing roller and for cleaning developer Powder 11 37 therefrom in which a rigid frame formed with one sur- [51] Int. Cl. B05c 11/10 face having two longitudinal edge areas Separated y a 53 Fidd f Search 1 /70 203 207 2 0 central recess extending the length thereof has a wick- 118/264, 269, 637; 355/15; 432/59; 15/2501 ing blanket, containing a release and off-set preventing fluid, stretched across its one surface to contact 5 References Cited the two longitudinal edge areas. The frame is resil- UNITED STATES PATENTS iently biased to forcibly engage the portions of the wicking blanket over the longitudinal edge areas of 3 2, 22% the frame against the pressure fixing roller. 317961183 3/1974 Thettu 118/70 3 Claims, 3 Drawing Figures RELEASE FLUID APPLICATOR FIELD OF THE INVENTION The present invention relates to an applicatorcleaner for applying a release and off-set preventing fluid to the surface of a cylindrical pressure fixing roller and for cleaning developer powder therefrom.

BACKGROUND OF THE INVENTION Electrographic copying machines generally use a developer or toner powder which is transferred to a sheet of paper in the same image pattern as appears on the original document being copied, which powder is permanently affixed to the paper. Most of the developer powders in the present use are made up primarily of thermoplastic resins which are affixed to the paper by raising the temperature of the powder to its melting point, causing the particles to coalesce and flow together and at the same time adhere to the receptor paper.

The heat fusing technique, while in widespread successful use, suffers from several drawbacks. First, the time required to bring the thermoplastic particles up to their melting point to effect fusion to the paper is usually the slowest step in the photographic copying process. More heat would speed up the process, but this is limited by the receptor paper sincethe temperature of the fusing system must always be below the char point of the paper. In order to speed up the fusing step, use has been made of lower melting point thermoplastic resins. However, this has produced other problems, such as poor character definition in the final image and the loss of sharpness in the image formations.

A second drawback of the heat fusing process is the presence of heat energy emanating from the fusing device, resulting in the general discomfort of persons working in the area surrounding the machine. A third drawback is the requirement that startup is not instantaneously achieved after a period of shutdown since the fusing device must'be brought up to proper operating temperature. And, in order to have the equipment ready to meet a copy demand anytime after start-up it must be kept at or near operating temperature resulting in a waste of heat energy during periods when the machine is not in use.

Recently, the drawbacks of heat fusing have been overcome by the use of developer powders that are pressure-fixable onto a paper receptor sheet. Thus, in place of a fusing device a pair of hard-surface cylindrical rollers are forced into peripheral contact and the receptor paper with the powder thereon is fed through the nip between the rollers to fIX the powder to the receptor in the pattern of the images on the original document being copied.

In pressure fixing it is important that in fixing the powder to the receptor sheet that the same is not disturbed as far as location on the receptor sheet, that the powder is not off-set from the desired image location which would distort the character of the image. Furthermore, it is necessary to compensate for the undesirable tendency of the receptor paper sticking to one of the pressure fixing-rollers after passing through the nip therebetween. And the inevitable small amount of developer powder adhering to the pressure fixing roller contacting it on the receptor sheet must be removed or it will later be undesirably transferred to a receptor sheet. These problems have previously been overcome by wicking an off-set preventing fluid, usually a silicone oil, from a reservoir onto the roller contacting the toner powder. However, it has been found that this causes a sufficient amount of the off-set preventing fluid to be transferred to the receptor paper to interfere with subsequent writing on the receptor paper with pencil or pen.

SUMMARY OF THE INVENTION The present invention provides an applicator-cleaner for applying a release and off-set preventing fluid to the surface of a cylindrical pressure-fixing roller and for cleaning developer powder therefrom. A rigid frame having a length corresponding to the length of the pressure fixing roller is formed with one surface having two longitudinal edge areas separated by a central recess extending the length of the frame and a wicking blanket containing a predetermined quantity of a release and off-set preventing fluid is secured to the frame and stretched across the one surface of the frame to contact the two longitudinal edge areas thereof. The support is resiliently biased in a direction to urge the one surface thereof toward contact with the pressure fusing roller to forcibly engage the portions of the wicking blanket over the longitudinal edge areas of the frame against the pressure fusing roller.

The applicator-cleaner of the present invention applies very small quantities of the release and off-set preventing fluid to the surface of the cylindrical pressure fixing roller uniformly throughout its useful life. The release and off-set preventing fluid is applied generally at the longitudinal edge area of the frame that is forward with respect to the direction of rotation of the pressure fixing roller and at the rearward longitudinal edge developer powder is cleaned from the pressure fixing roller. The recess separating the longitudinal edge areas effectively segregates the cleaning area from the release and off-set preventing fluid applicating area so that all of the useable off-set preventing fluid can be wicked from the blanket.

THE DRAWING In the drawing:

FIG. 1 is a perspective view showing the top, one longitudinal edge and one end of one portion of an applicator-cleaner constructed in accordance with the present invention;

FIG. 2 is a longitudinal elevation view of an applicator-cleaner constructed in accordance with the present invention including the portion illustrated in FIG. 1; and,

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The applicator-cleaner of the present invention comprises a rigid frame 10, a wicking blanket 12 containing a release and off-set preventing fluid and resilient biasing means comprising a pair of helical compression springs 14 and 15.

The frame 10 is, for example extruded aluminum, and it has a length corresponding to the length of a pressure fixing roller 17 with which the applicatorcleaner is to be used. It is formed with one surface having two longitudinal edge areas 19 and 20 separated by a central recess 22 extending the length of the frame 10. The opposite surface of the frame is also recessed and internally formed with a rectangular longitudinal slot 24 extending parallel to the length of the first surface to be slidably received on a support bar 26 which is complementary in cross-sectional shape to the slot 24.

The frame 11) is further formed adjacent and parallel to its longitudinal edges with a pair of opposed longitudinally extending cylindrical apertures 28 and 29. Each of the apertures 28 and 29 is slotted through its adjacent edge wall to permit access through an edge wall into the corresponding aperture, the communicating slots having a lesser width than the diameter of the apertures 28 and 29.

The wicking blanket 12 is, for example, a felt wicking material, and it has a length equal to that of the frame and a width greater than that of the frame. The wicking blanket is stretched across the surface of the frame containing the recess 22 to contact the longitudinal edge areas 19 and 20 thereof. The edges of the wicking blanket are similarly folded back and inserted into the apertures 28 and 29 wherein they are retained by similar retaining rods 31 and 32 respectively, having diameters less than that of the apertures 28 and 29 and inserted through the folded back edges of the wicking blanket 12 down the apertures 28 and 29. The retaining rods 31 and 32 are joined by a U-shaped connecting portion 33 at right angles to the rods 31 and 32 which defines a handle for the frame 10 with the wicking blanket 12 thereon.

In the photocopying machine a pair of immovable brackets 35 and 36 extending from the main vertical machine walls 38 and 39, respectively, pivotally support the applicator-cleaner over the pressure roller 17. The brackets 35 and 36 are formed with wrap around portions 37 to provide facing vertical portions of each bracket 35 and 36 through which facing pivot pins 41 are threaded to engage opposed recesses formed near the top of each of a pair of similar end pieces 44 and 45 of the applicator-cleaner. Each end piece 44 and 45 is generally cylindrical with a pair of opposed flanges 47 and 48 extending perpendicular to its axis at its base. Attached to the flanges 47 and 48 of the end pieces 44 and 45 are the ends of a strengthening bar 49 extending between the end pieces 44 and 45 parallel to the frame support bar 26. Each end piece 44 and 45 is formed with a central axially extending rectangular aperture 52 in which a rectangular shaft 54 is slideable. One end of each shaft 54 is secured by a screw 55 to the frame support bar 26 and the opposite end thereof is formed with a retaining flange at 90 to its length. The helical compression springs 14 and 15 surround the rectangular shafts 54 and are captured between the end pieces 44 and 45, respectively, and the frame support bar 26. The retaining flanges at the upper ends of the shafts 54 prevent the compression springs 14 and 15 from pulling the shafts all the way through the end pieces 44 and 45 when the frame 10 is pivoted away from its contact with the pressure roller 17.

In use, the frame 10 with a wicking blanket 12 attached thereto and a handle 33 extending therefrom, as illustrated in FIG. 1, is picked up by the handle 33. The frame support bar 26 and the remainder of the pivotal structure is pivoted away from its alignment with the axis of the pressure roller 17 to the left as viewed in FIG. 3. The longitudinal slot 24 in the frame 10 is aligned with the support bar 26 and the frame is then slid onto the support bar. Finally, the handle 33 is grasped and pushed to the right as viewed in FIG. 3 into a slot in the bracket 36 to pivot the applicator-cleaner into the position illustrated in FIGS. 2 and 3 with a line connecting the pivot axis of the applicator-cleaner to the axis of rotation of the pressure roller 17 passing centrally through the width of the frame 10 and the wicking blanket 12. The applicator-cleaner will then be in a stable position with the helical springs 14 and 15 exerting generally equal pressure along both of the longitudinal edge areas 19 and 20.

FIG. 3 illustrates the applicatorcleaner in use with the pressure roller 17 rotating in a clockwise direction. Toner powder particles 57 adhering to the pressure roller 17 are removed by the wicking blanket over and adjacent the left longitudinal support area 19 of the frame 10 and an off-set preventing fluid 59, for example silicone oil, is applied to the pressure roller 17 by that portion of the wicking blanket over and adjacent the right longitudinal edge area 20. The cleaning and applicating functions are in this manner effectively separated so that the toner powder 57 being cleaned from the pressure roller 17 does not contaminate that portion of the wicking blanket where the silicone oil 59 is being applied, thereby allowing the applicator-cleaner to operate effectively until all of the usable off-set preventing fluid has been wicked out of the blanket 12 onto the pressure roller 17.

In specific tests, the applicator-cleaner illustrated and described herein was utilized in a pressure-fixing system wherein the pressure rollers apply a fixing pressure of 3.6 kilograms per lineal millimeter along a length of 271 millimeters. A polyester felt wicking blanket 12 having a width of millimeters and in contact with the pressure roller 17 over 20 millimeters of its width was used. The frame 10 and the wicking blanket were forced into contact with the pressure roller 17 by the springs 14 and 15 with a total force of 4.5 kilograms. Five to nine grams of Dow-Corning No. 200 Fluid20OCS, a silicone oil, was used with a corresponding copy life of the applicator-cleaner of 18,000 to 40,000 copies, respectively.

I claim:

1. An applicator-cleaner for applying a release and off-set preventing fluid to the surface of a cylindrical pressure fixing roller and for cleaning developer powder therefrom, comprising:

a rigid frame having a length corresponding to the length of a said pressure fixing roller and formed with one surface having two longitudinal edge areas separated by a central recess extending the length of said frame,

a wicking blanket secured to said frame and stretched across said one surface of said frame to contact said two longitudinal edge areas thereof,

a predetermined quantity of a release and offset preventing fluid contained in said wicking blanket, and

resilient biasing means for urging said one surface of said rigid frame toward contact with the pressure fusing roller to forcibly engage the portions of said wicking blanket over said longitudinal edge areas of said frame against the pressure fusing roller.

2. The applicator-cleaner of claim 1 including means supporting said rigid frame and said resilient biasing means for pivotal movement about an axis parallel to the axis of the fusing cylinder, said resilient biasing means being positioned between said pivot axis and said slot in said rigid frame to slidably receive and support said rigid frame, said bar being positioned between said rigid frame and said resilient biasing means, whereby said rigid frame may be pivoted away from the fusing cylinder and slidably removed from said supporting means and replaced to replace said wicking blanket. 

1. An applicator-cleaner for applying a release and off-set preventing fluid to the surface of a cylindrical pressure fixing roller and for cleaning developer powder therefrom, comprising: a rigid frame having a length corresponding to the length of a said pressure fixing roller and formed with one surface having two longitudinal edge areas separated by a central recess extending the length of said frame, a wicking blanket secured to said frame and stretched across said one surface of said frame to contact said two longitudinal edge areas thereof, a predetermined quantity of a release and offset preventing fluid contained in said wicking blanket, and resilient biasing means for urging said one surface of said rigid frame toward contact with the pressure fusing roller to forcibly engage the portions of said wicking blanket over said longitudinal edge areas of said frame against the pressure fusing roller.
 2. The applicator-cleaner of claim 1 including means supporting said rigid frame and said resilient biasing means for pivotal movement about an axis parallel to the axis of the fusing cylinder, said resilient biasing means being positioned between said pivot axis and said rigid frame to permit said rigid frame to be pivoted away from the fusing cylinder for replacement of said wicking blanket.
 3. The applicator-cleaner of claim 2 wherein said rigid frame is formed with a longitudinal slot extending parallel to the length of said one surface thereof and wherein said means supporting said rigid frame includes a bar complementary in cross-sectional shape to said slot in said rigid frame to slidably receive and support said rigid frame, said bar being positioned between said rigid frame and said resilient biasing means, whereby said rigid frame may be pivoted away from the fusing cylinder and slidably removed from said supporting means and replaced to replace said wicking blanket. 